In these years, various techniques are being developed in order to help drivers drive safely. One of the techniques is a technique for recognizing a recognition target in an image captured by a camera mounted on a vehicle. When a recognition target has been recognized, a warning or the like is issued to a driver.
For example, when the camera is installed inside the vehicle, the camera captures images of the outside through a sheet of glass. In this case, so-called “reflections” might occur in an image captured in an environment in which an intense light source such as the sun exists. Reflections are phenomena in which light from objects inside the vehicle is reflected by a surface of the sheet of glass or the like and detected by a sensor of the camera installed inside the vehicle, thereby causing a captured image to include images of the entirety or part of the objects inside the vehicle. Reflections occur when there is an object whose surface reflects light, such as a sheet of glass, in an image capture direction of the camera as in the case of the camera installed inside the vehicle. In the following description, an image including reflections will be referred to as a reflection image.
When a recognition target is to be recognized in a reflection image, recognition accuracy decreases. Therefore, an object recognition device for properly recognizing a recognition target even in a reflection image has been disclosed. The object recognition device is disclosed in Japanese Laid-open Patent Publication No. 2010-61375. The object recognition device sequentially captures images of a region in a certain direction of a vehicle and extracts a plurality of feature points from each image. The object recognition device then removes fixed feature points whose coordinates remain the same in the images from a plurality of feature points extracted from a latest image. Finally, the object recognition device recognizes an object on the basis of the feature points in the latest image from which the fixed feature points have been removed.